1. Field of the Invention
The present invention relates to a film feeder for still cameras loaded with a film cartridge in which a spool shaft of the cartridge is turned in the forward direction or in the reverse direction, to feed a roll film through a lead-out opening to the outside or rewind it.
2. Related Background Art
For example, U.S. Pat. Nos. 4,832,275 and 4,834,306 disclose a structure of a film cartridge which includes a cylindrical portion having therein a spool shaft for storing a photographic roll film, and a film lead-out portion extending in the tangential direction of and integrally provided with the cylindrical portion and for accommodating the leading edge of the film in a linear state. This type of film cartridge is different in structure from a 135 type film cartridge which is generally used at present. The above-mentioned film cartridge is so constructed that it is specially handled when it is first loaded in a camera, since the leading edge of the film is accommodated in the foregoing lead-out portion so as not to be exposed to light. When the film cartridge is loaded in the camera, the spool shaft is rotated by a drive system of the camera, to consequently send out the leading edge of the film through a lead-out opening of the cartridge.
When the cartridge having such structure is taken out of the camera after rewinding the film upon the completion of photographing, the leading edge of the film remains in the cartridge. In addition, the delivery of the film loaded in the camera can be automatically performed by rotationally driving the spool with the aid of an electric motor, and accordingly, the film can be readily loaded into the camera, which results in an easier handling of the film for the operator.
Nevertheless, in a camera in which a film cartridge having above-mentioned structure is to be loaded, the existing film feeder manufactured for a 135 type film cartridge is incapable of being used, because the film needs to be led out and rewound by rotationally driving the spool of the cartridge.
Suitable camera structures and an internal mechanism thereof capable of loading this type of film cartridge, for example, a mechanism that can be used to send the film out of the cartridge, wind up the film by one frame, and rewind the film into the cartridge, have not been satisfactorily developed. Therefore, the development of a camera having a film lead-out mechanism, a wind-up mechanism, and a rewinding mechanism which will realize the advantages of the above-mentioned structure of the cartridge, is strongly desired.
What is desired with regard to the constitution of such camera, is that the film lead-out, wind-up, rewind operation and the like mentioned above can be executed by a film drive mechanism having a simple structure composed of the minimum number of constituent parts as needed; the working parts are efficiently arranged and the entire device has a small and compact configuration; and the working parts can be stably and reliably operated. Any measures which completely satisfy such requirements need to be adopted.
By way of example, one of the requirements for the constitution of the film feeder for such cameras is to suitably and reliably control the operation of the film lead-out from the film cartridge and the operation of the film rewind into it, through a single drive source and a rotation transmission system driven from the source.